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| Pentax Optio 550 | Olympus C-50 Zoom |
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| Canon PowerShot S50 | Nikon Coolpix 5000 |
In the table below we're only measuring colour. The RGB values were measured from a VGA reduced image (to average colors, remove noise and eliminate JPEG artifacts) using the Eyedropper tool in Photoshop with a 5 by 5 Average Sample Size.
| Patch | Pentax Optio 550 |
Olympus C-50 Zoom |
Canon PowerShot S50 |
Nikon |
| Black | 26,25,25 | 37,31,40 | 33,34,35 | 19,20,19 |
| Middle Gray | 95,92,93 | 105,105,116 | 96,100,103 | 91,91,91 |
| White | 217,211,210 | 218,221,227 | 208,210,211 | 209,209,205 |
| Magenta | 210,18,99 | 201,10,127 | 199,44,121 | 219,37,93 |
| Red | 196,14,26 | 199,9,48 | 197,37,46 | 207,26,23 |
| Yellow | 204,196,45 | 215,204,20 | 203,193,23 | 212,189,47 |
| Green | 19,149,74 | 18,142,77 | 9,136,72 | 0,130,68 |
| Cyan | 23,178,227 | 8,149,202 | 6,144,214 | 1,153,200 |
| Blue | 45,28,106 | 53,35,121 | 29,41,109 | 33,44,98 |
The Optio 550 produced pleasing, balanced results with fairly good saturation in each of the primary colors. Automatic white balance delivered good results with an almost perfect mid-gray. Compared to the other five megapixel digital cameras the Optio 550's colors were slightly 'lighter' but had similar saturation.
Shots here are of the PIMA/ISO 12233 standard resolution test chart (more of which are available in our comparison database). This resolution chart allows us to measure the actual performance of the lens and sensor system. It measures the ability of the camera to resolve lines at gradually higher resolutions and enables us to provide a definitive value for comparison purposes. Values on the chart are 1/100th lines per picture height. So a value of 8 equates to 800 lines per picture height.
Studio light, cameras set to auto, all settings factory default. Exposure compensation +0.7 EV for all cameras (to compensate for the white background). Click on the camera name below the crops to download the full resolution chart (large JPEG's).
| Horizontal resolution | Vertical resolution | 5 degree diagonal res. |
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| Pentax Optio 550 (2,254 KB) | ||
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| Olympus C-50 Zoom (2,152 KB) | ||
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| Canon PowerShot S50 (2,011 KB) | ||
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| Nikon Coolpix 5000 (1,609 KB) | ||
Measurable findings (three measurements taken for each camera)
| Camera | Measurement | Absolute Res. | Extinction Res. |
| Pentax Optio 550 | Horizontal LPH | 1350 | 1500 |
| Vertical LPH | 1250 | 1450 | |
| 5° Diagonal LPH | + 1000 | n/a | |
| Olympus C-50 Zoom | Horizontal LPH | * 1425 | * 1650 |
| Vertical LPH | * 1300 | * 1650 | |
| 5° Diagonal LPH | + 1000 | n/a | |
| Canon PowerShot S50 | Horizontal LPH | 1425 | 1650 |
| Vertical LPH | 1300 | 1600 | |
| 5° Diagonal LPH | # + 1000 | n/a | |
| Nikon Coolpix 5000 | Horizontal LPH | * 1350 | * 1500 |
| Vertical LPH | * 1200 | 1500 | |
| 5° Diagonal LPH | + 1000 | n/a |
Definition of terms
| LPH | Lines per Picture Height (to allow for different aspect ratios the measurement is the same for horizontal and Vertical) |
| 5° Diagonal | Lines set at 5° diagonal |
| Absolute Resolution | Still defined detail (below Nyquist frequency*) |
| Extinction Resolution | Detail beyond camera's definition (becomes a solid gray alias) |
| n/a | Not Available (above the capability of the test chart) |
| n/v | Not Visible (not visible on test results) |
The Optio 550 does reasonably well (average five megapixel performance). It appears to be at least a match for Nikon's Coolpix 5000, surprisingly it didn't produce as much detail as the Olympus C-50 Zoom which it did beat in our side-by-side comparison on the previous page (probably a factor of the C-50 Zoom's noise level in that shot). It's a fairly good performance if you consider the Optio 550's five times optical zoom.
